This letter presents a D-band low-noise amplifier (LNA) for joint radar-communication applications in 22-nm CMOS technology. The 4-stage LNA uses transistor switching and bias class changes to achieve dual-mode functionality. In the radar mode, the LNA achieves gain of 17 dB, noise figure (NF) of 7.7 dB, 3-dB bandwidth (BW) of 117–129 GHz, and IP1dB of −20 dBm, respectively. In the communication mode, the LNA achieves gain of 22.6 dB, NF of 8.5 dB, BW of 115.9–128.9 GHz, and IP1dB of −29 dBm, respectively. The power consumption for the radar and communication modes is 13 and 12.2 mW, respectively. The LNA has a core area of $0.06~text {mm}^{2}$